Device for hermetically sealing the opening for the winding stem in a watch dome

ABSTRACT

A device for hermetically sealing the opening in a watch dome for a winding stem characterized by a hollow crown provided at one end of the winding stem, this crown having a circularlyshaped wall extending around a fixed projecting part of the device, wherein the fixed part comprises at least one sealing ring, a support element and a cap which overlaps the ring, the cap being supported on a fixed base with a press fit so that the sealing ring is pressed against the support element in an axial direction.

United States Patent 1 Stebler 51 May 16, 1972 DEVICE FOR HERMETICALLY SEALING THE OPENING FOR THE WINDING STEM IN A WATCH DOME [72] Inventor: Walter Stebler, Konzumweg l0, Preterlen,

Conton of Bern, Switzerland [22] Filed: Dec. 21, 1970 [21] Appl. No.: 99,992

[30] Foreign Application Priority Data Dec. 23, 1969 Switzerland ..19120/69 [52] US. Cl ..58/90 B, 277/187 [51] Int. Cl. ..G04b 37/10 [58] Field otSearch ..58/90 B; 277/187 [56] References Cited UNITED STATES PATENTS 2,284,594 5/1942 Schmitz. ..277/187 HHHH 2,771,734 11/1956 Morf .,..58/90B 3,164,954 1/1965 Soguel ....58/90 B 3,178,879 4/1965 Nardin ..277/1 87 FOREIGN PATENTS OR APPLICATIONS 331,280 10/1958 Switzerland ..58/90 B Primary Examiner-Robert 1. Smith AttorneyStevens, Davis, Miller & Mosher [57] ABSTRACT 3 Claims, 2 Drawing Figures PATENTEDMM 16 I912 SHEET 2 BF 2 DEVICE FOR HERMETICALLY SEALING THE OPENING FOR THE WINDING STEM IN A WATCH DOME BACKGROUND OF THE INVENTION 1. Field of Invention The present invention has to do with a device for the hermetic sealing of the opening for the winding stem in a watch dome.

2. Description of the Prior Art Numerous devices of this kind are already known in which the sealing ring is arranged in the inside of the crown or in the inside of the tube which is provided for guiding the winding stern and is attached to the dome. Devices of this kind are also known which have several sealing rings of rectangular or round shape. If the sealing ring or rings is arranged in the inside of the crown then it is difficult to produce them because of the fact that the walls of the crown must be kept very thin, so that their dimensions do not become excessive. The fasteners of the ring thus lose the desired security. For the same reason rings of greater sizes, which, as is known, possess certain advantages because of their flexibility, cannot be used. When-the sealing ring is arranged inside the tube and within the wall of the dome then its dimensions are limited by the thickness of the dome.

SUMMARY OF INVENTION The purpose of the present invention is thus to create a device of the kind described which can carry out the task it is supposed to do in a better way than was previously the case.

For this purpose the device according to the inventionis characterized by the fact that a hollow crown is provided at one end of the winding stem, this crown having a circularlyshaped wall extending around a fixed projecting part of the device, and that this fixed part comprises at least one sealing ring, a support element and a cap which overlaps the ring, said cap being supported on a fixed base with a press fit in such a way that the sealing ring is pressed against the support element in the axial direction.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENTS The device which is represented in FIG. I has a hollow crown l which is screwed into the outer end of the winding stem 2, the wall of said crown extending about the fixed part of the device. This fixed part is composed of the tube 5, the sealing rings 7 and l l, the casing 8 and the cap 12. The fastening of the tube 5 onto the outside wall of the dome 4 is provided by means of inserting its inside end into a cylindrical opening 3 which passes through the wall. Thus the band 6 of the tube 5 lies on the outside surface of the dome and the part of the tube 5 which juts outwards serves as the guide element for the sealing ring 7 cut off with a rectangular cross section. Ring 7 surrounds the tube 5 over the entire length of its outside part and lies against the outer wall of the dome 4. The tubular-shaped easing 8 is also provided for securing the ring 7. The inside diameter of the casing is selected in such a way that the casing lies against the ring 7 with a press fit. Thus the ring 7 is held stationary in a position which is pressed in the radial direction. The casing 8 has in its outside areas a ring-shaped flat shoulder 9. The upper part of this casing, which is limited by the cylindrical surface 10, has a smaller thickness than the lower part. Also belonging to the fixed part of the device are a second sealing ring 11 and a cap 12. The sealing ring 11 which is formed with a rectangular cross section, the height of which is smaller than the thickness, has a central opening the inside diameter of which is adjusted to that of the winding bar. As an example, the diameter of the bar can be 0.45 mm and the outside diameter of the tube which corresponds to the inside diameter of the sealing ring 7 can be 0.8 mm.

The cap 12 has the shape of a small dome or shell which is formed of a cylindrical side wall and a bottom, whereby the bottom has a central opening 13 which is of somewhat greater dimensions than the dome itself and which pennits the passing of the bar through the bottom of the cap. The bottom of the cap 12 has a flat inside surface which presses against the sealing ring 11. The outside surface of the bottom has a curved convex shapewhich corresponds to the shape of the inside surface of the hollow space 14 of the crown. In an expanded part of the hole 13, which runs into the inside surface of the bottom of the cap, an additional smaller packing 11a is interposed. The fastening of the cap 124; onto the fixed part of the device is done by pressing the wall of the cap 12 onto the outside surface 10 of the casing 8. These parts are fastened to one another with a press fit and in such a way that the sealing'rings 7 and 11 are pressed against one another. In a variation of this, the casing 8 could also be fastened directly onto the wall of the dome, although this does not seem to be necessary in all cases.

For its fastening to the end of the stem 2 the crown 1 has a dull threaded hole 15 which is provided in the bottom of the hollow space of the crown and into which the end of the stem 2 is screwed. The hollow space of the crown comprises the tube 5, the sealing rings 7 and 11 and the parts 8 and 12 which fasten the sealing rings to the tube 5. The solid part of the device thus extends all the way inside the top of the crown.

Since the sealing ring 1 l is pressed together in the axial direction solidly between the bottom of the cap 12 and the upper edge of the ring 7 and since it is held in place in the radial direction through the wall of the cap 12, the edge of its central opening lies solidly against the stem 2 under the effect of thepressure to which it is subjected. Thus a good tightness is achieved. A further advantage of the crown which has been described lies in its simple construction which results in the fact that the individual parts are easy to work out. The friction between the fixed and the moving part of the device thus occurs on the bushing of the dome 4 through the central opening of the ring 11. The latter can be lubricated with synthetic grease for the purpose of improving its tightness and the friction conditions. The contact surfaces through which dust and water can penetrate into the dome are reduced to a minimum, since their diameter is the same as that of the stem. Furthermore, the fixed parts of the device can be designed in such a way that these parts can secure the two sealing rings 7 and 11 between them with absolute reliability without imparting excessive dimensions to the device.

An embodiment is shown in FIG. 2 in which the crown I and the winding stem 2 are arranged in the same way-as in FIG. 1. Furthermore, the opening 3 which is provided in the dome 4 and is intended for the passing through of the winding stem 2 can have the same dimensions as in FIG. 1. The tube 16 has a band 17 of rectangular shape in the part which projects from the dome 4. The shape of the cap 18 is similar to that of the cap 12. Its side wall, however, is somewhat wider and is pressed against the outside surface of the band 17. The main difference between the two forms of design described here is that instead of the two sealing rings 11 and 7 only one sealing ring 19 is provided for in the second form of design. The profile of the ring 19 has the form of an angle the horizontal part of which is pressed in the axial direction between the upper edge of the tube 16 and the bottom of the cap 18. The ring 19 also has a side wall which is pressed in the radial direction between the tube itself and the side wall of the cap 18. Thus the sealing ring 19 replaces the two fittings 7 and 11 of the first form of design. The slackness (play) which exists between the stem 2 and the inside wall of the tube 16 allows the ring 19 to deform itself so that, under the effect of the forces exerted through the cap, it lies on the side surface of the stem 2 and assures the tightness of the passage of the stem through the tube.

The arrangement described permits the passage of the bar through the dome wall up to a pressure of 40-50 atm with a margin of safety of 100 percent of remaining completely airtight.

The additional packing 11a can also be arranged in one of the milled recesses in the bent outside surface of the cap 12. Because of the simpler construction, however, the arrangement in FIG. 1 with the packing immersed in the inside surface of the bottom is to be preferred.

Having described a preferred embodiment of my invention but not intending to so limit it, I hereby claim as my invention:

1. A device for hermetically sealing the opening in a watch dome for a winding stem, comprising a hollow crown which is fastened to an end of said stem, said crown having a circularshaped wall which extends over a protruding fixed part of the device, said fixed part having a plurality of tubular-shaped holding parts which are arranged coaxially to said stem and a cap which is supported on the outside tubular-shaped part with a press fit, a first sealing ring provided between said holding parts and a second sealing ring disposed between the upper edges of said holding parts and said cap, said sealing rings being pressed against one another through said cap.

2. A device according to claim 1, wherein the hollow space of said crown has a bent inside surface, the outside surface of the cap which is turned against said inside surface being correspondingly bent.

3. A device according to claim 1, wherein said winding stem passes through said sealing rings and said cap, and the bottom of said crown has a dull threaded hole into which said winding stem is screwed. 

1. A device for hermetically sealing the opening in a watch dome for a winding stem, comprising a hollow crown which is fastened to an end of said stem, said crown having a circular-shaped wall which extends over a protruding fixed part of the device, said fixed part having a plurality of tubular-shaped holding parts which are arranged coaxially to said stem and a cap which is supported on the outside tubular-shaped part with a press fit, a first sealing ring provided between said holding parts and a second sealing ring disposed between the upper edges of said holding parts and said cap, said sealing rings being pressed against one another through said cap.
 2. A device according to claim 1, wherein the hollow space of said crown has a bent inside surface, the outside surface of the cap which is turned against said inside surface being correspondingly bent.
 3. A device according to claim 1, wherein said winding stem passes through said sealing rings and said cap, and the bottom of said crown has a dull threaded hole into which said winding stem is screwed. 